He was drafted by the Florida Panthers with the 7th overall pick in the 2004 NHL Entry Draft. He also played in the NHL for the Florida Panthers for 6 seasons. He was traded by the Florida Panthers to the Chicago Blackhawks for defenceman Brian Campbell on June 24, 2011.[1]

He played 6 games with the Blackhawks and played a season with their AHL farm team, the Rockford IceHogs. On July 5, 2013, Olesz signed a 1 year deal with the New Jersey Devils.[2] On November 21, 2013, he signed a contract with SC Bern of the NLA.[3]